Text preview for : al1702_book_133.pdf part of Acer AL1702 17-inch LCD Monitor
Back to : al1702_book_133.pdf | Home
Service Manual
17-inch LCD Monitor
AL1702
Service Manual Versions and Revision
N o. Ve rs ion R e le as e D ate R e vis ion
1. 1.0 May 12, 2004 O riginal release
Copyright Trademarks
Copyright 2004 LiteOn Technology Corp. LiteOn is a registered trademark of LiteOn
Technology Corp.
All Rights Reserved
All other trademarks are the property of their
This manual may not, in whole or in part, be
respective owners.
copied, photocopied, reproduced, translated, or
converted to any electronic or machine readable
form without prior written permission of LiteOn
Technology Corp.
ACER AL1702 Service Manual.
Printed in Taiwan.
AL1702
1) Circuit Description
1. Power Board Operation Therory -------------------------------------------------------------------------------------------- 3
2. Inverter -------------------------------------------------------------------------------------------------------------------------- 4
3. Interface ------------------------------------------------------------------------------------------------------------------------- 5
3.1 Top --------------------------------------------------------------------------------------------------------------------------- 5
3.2 Power ------------------------------------------------------------------------------------------------------------------------ 5
3.3 VGA & DDC interface ----------------------------------------------------------------------------------------------------- 5
3.4 Scaler MST8111A --------------------------------------------------------------------------------------------------------- 5
3.5 Panel interface -------------------------------------------------------------------------------------------------------------- 5
3.6 Audio ------------------------------------------------------------------------------------------------------------------------ 7
4. Others --------------------------------------------------------------------------------------------------------------------------- 7
4.1 Detection of POWER switch status ------------------------------------------------------------------------------------ 7
4.2 Display mode identification ---------------------------------------------------------------------------------------------- 7
4.3 Power ON sequence ------------------------------------------------------------------------------------------------------ 8
4.4 Power OFF sequence ----------------------------------------------------------------------------------------------------- 8
4.5List of I/O Pin Assignments of the I307 -------------------------------------------------------------------------------- 9
2) Trouble Shooting
1. No display of screen (Screen is black, color of LED is amber) -------------------------------------------------------- 11
2. Nothing displays on screen (Screen is black, color of LED is green) ------------------------------------------------ 12
3. Checking the back light unit ----------------------------------------------------------------------------------------------- 15
4. Abnormal screen------------------------------------------------------------------------------------------------------------- 16
Page 1
AL1702
6. Abnormal plug and play operation --------------------------------------------------------------------------------------- 18
7. Checking the interface circuit of sync signal ---------------------------------------------------------------------------- 19
7.1 Checking the control circuit of horizontal sync pulse ------------------------------------------------------------- 19
7.2 Checking the control circuit of vertical sync pulse ---------------------------------------------------------------- 19
8 Checking the resolution change IC movement -------------------------------------------------------------------------- 20
9. Checking the DC/DC converter circuit ----------------------------------------------------------------------------------- 21
10. Checking the Audio circuit [option] -------------------------------------------------------------------------------------- 22
11. Checking inverter board circuit -------------------------------------------------------------------------------------------- 23
12. Power board ------------------------------------------------------------------------------------------------------------------ 24
3) Spare Parts
Recommended Spare Parts List ------------------------------------------------------------------------------------------------- 25
Page 2
AL1702
1) Circuit Description
1. Power Board Operation
1.1 Line filter consists of C801, T801, C802, C803, C804. It eliminates high frequency interference to meet EMI's
requirement.
1.2 Rec & Filter
Bridge diode D801 converts AC source into pulsed DC. This pulsed DC is smoothed and filtered by C805.
R802 is an NTC ( negative thermal coefficient ) resistor, used to reduce inrush current to be within safe range.
1.3 Power transformer :
T802 converts energy for square wave from power source C805 to secondary side to generate +12V and +22V.
1.4 Output :
The square wave from T802 is rectified by D809, D811, then filtered by C822, C817 to generate +12V and +22V
respectively. I804 is the regulator for +5V output.
1.5 Driver :
Q803 drive T802 from PWM control of I801 for power converted.
1.6 FB :
Negative feedback CKT consists of photo coupler I802 and adjustable regulator I803. It can maintain output
voltages +22V and +12V at a stable level.
1.7 PWM :
1.7.1 Start : When power is turned on, Q801 conducts due to bias from C805 and R805,R803. C807 is charged a
16 volt and a starting current about 0.3mA to pin 7 of I801. I801 starts to oscillate and outputs a pulse
train through pin 6 to drive Q803.
1.7.2 OPP : When Q803 turns on, C805 supplies a linearly increasing triangle current through the primary
inductance of T802 to the driver Q803, once the peak value of this current multiplied by R811 exceeds1
volt, pulse train will be turn off immediately to protect Q803, T802 from being burned out.
1.7.3 Regulation : If output voltage +22V or 12V goes up, the R terminal of I803 gets more bias, accordingly
photo transistor and photo diode flows more current. The voltage of pin 2 of I801 goes up too, making
the pulse width of pin 6 of I801 to become narrower. So the output voltage +5V will be pulled down to a
stable value.
1.7.4 OVP : If +22V or 12V goes up too much, the induced voltage on pin 4 of T802 becomes large also.
Suppose that it is over 18 volts, ZD801 conducts, pin 3 of I801 is pulled up over 1 volt. The pulse train at
pin 6 of I801 goes down to zero, shutting Q803 off immediately.
1.7.5 SCP : If output terminal is short to ground, photo transistor does not conduct, hence Q806 does not
conduct either. Then oscillation of I801 is stop, shutting Q803 off immediately.
Power Board Block Diagram
Line Rec. & Power
Filter Filter Transformer Outpur Rec. & Filter
PWM Driver
FB
Page 3
AL1702
2. Inverter Operation
This unit operates on an output voltage of 22V from power source.
2.1 VCC: When On/Off pin of P802 is high level input, Q106 turns on and provides +5VDC for I101 power supply.
2.2 Control IC: I101 (OZ960S)
2.2.1 Enable : When pin 3 of I101 is over 1.5V, I101 works. If it is under 1.5V, I101 turns off.
2.2.2 OSC: When I101 enabled, R108/C115 (pin 17/pin18 of I101) determine the operating frequency.
2.2.3 SST: C104 (pin 4 of I101) provides soft start function.
2.2.4 Ignition: R109 (pin 8 of I101) provides higher operating frequency for more striking voltage until regula-
tion of feedback of lamp current. C103 (pin 1 of I101) determine the striking time.
2.2.5 Dimming control: The divided voltage of R106/R105/R104 control the duty pulse of burst-mode to drive
Q105 and perform a wide dimming control for the CCFL. The burst-mode frequency is determined by C116.
2.2.6 Regulation: Pin 9/pin 10 of I101 provide regulation of the CCFL current from feedback. The non-inverting
reference (pin 10 of I101) is at 1.25V nominal.
2.3 Protection: Open-lamp protection in the ignition period is provided through both pin1 and pin 2 of I101 to ensure
a rated voltage is achieved and a required timing is satisfied.
Removal of the CCFL during normal operation will trigger the current amplifier (pin 9/pin 10 of I101) output and
shuts off the inverter. This is latch function.
2.4
2.4.1 Output drivers: The configuration prevents any shoot-through issue associated with bridge-type power
conversion applications. Adjusting the overlap conduction between I102 P-MOSFET and I103 N-MOSFET,
I101 N-MOSFET and I103 P-MOSFET, the CCFL current regulation is achieved.
2.4.2 Full-bridge switching/Transformer: I102/I103 /C123/T101 compose full-bridge switching to convert DC
into AC for driver the CCFL.
2.5 Detection: C128/C129/C132/D115/D114/C118 detect the output voltage and ensure a rated voltage by pin2 of
I101.
2.6 Feedback: D116/D117/R120/D108/R116 sense the lamp current for negative feedback and regulation. The divided
voltage on R116 will be at 1.25V.
Inverter Circuit Block Diagram
VCC
Regulator
VDD
Control IC : OZ960 Full-bridge switching Lamp
Transformer
ON / OFF U.V.P. Enable Output driver
OSC Protection Detection
SST Ignition
Brightness Dimming
control Regulation Feed back
control
Page 4
AL1702
3. Interface Operation
3.1 Top (Circuit diagrams MAIN PWB 2 of 8)
This page is function block. (1) power. (2) VGA & DDC interface. (3) scaler MST8111B. (4) panel interface. (5)
audio (option).
3.2 Power (Circuit diagrams MAIN PWB 3 of 8)
3.2.1 P301 connector
A 5V power supply for LCD module, MCU, logic. And a 12V power supply for audio function. It is
generated from the P301 connector.
3.2.2 I301 : 3-terminal regulator
A 2.5V power supply for scaler IC I305, it is generated from the 5V source.
3.2.3 I302 : 3-terminal regulator
A 3.3V power supply for scaler I305, it is generated from the 5V source.
3.2.4 Q303, I312 : ON/OFF control for LCD module power
ON/OFF control (PANELVCC_EN) is performed for power ON/OFF and also for the power saving
sequence.
3.2.5 R306 : ON/OFF control for LCD module back light power
ON/OFF control (BKLT_EN) is performed for black light power ON/OFF and also for the power saving
sequence.
3.2.6 Q301,Q302 : Adjust back light luminance for LCD module
It is adjusted back light luminance control (BKLT_ADJ) is performed for the back light luminance.
3.3 VGA & DDC interface (Circuit diagrams MAIN PWB 4 of 8)
The analog video signals input, the AC-coupled video signal video signal is used to clamp the black level at
0V. and H/V sync to sclaer, and DDC plug & play function.
3.3.1 P302 connector
The video input signals from the P302 connector.
3.3.2 I304DDC EEPROM
This IC is support DDC2B of the VESA standard, also plug and play for the PC host.
3.4 Scaler MST8111B (Circuit diagrams MAIN PWB 5 of 8)
The I305 is scaled converter LSI for the LCD monitor.
The analog R, G, B signal input entered from the video input circuit is converted into the digital data of video
signal through the incorporated A/D converter. Based on this conversion, this device performs interpolation
during pixel extension. These interpolation digital data are transformed to LVDS signal. The I305 source
voltage is 3.3V and 2.5V, the device clock frequency is 14.318 MHz. The device control signal is from MCU
through the 3-wire bus.
The I305 scaler has support OSD function.
3.5 Panel interface (Circuit diagrams MAIN PWB 6 of 8)
3.5.1 P305 connector
The P305 is LVDS bus, output to LCD module. The output voltage is 5 voltage.
3.5.2 MCU (Circuit diagrams MAIN PWB 7 of 8)
The I307 MCU is system processor. It can programmed scaler, control power save sequence for the
system, input keypad function, output LED, control audio function, and ISP / DDC2Bi function.
Page 5
AL1702
3.5.3 X302 crystal
The X302 crystal is 11.0592MHz, support the operated clock to the MCU.
3.5.4 Reset circuit
The C396, R379, D316 is support reset signal to the MCU, then MCU have output hardware reset signal
(HWRESET) to the scaler.
3.5.5 I308EEPROM
The I308 is 24LC16 EEPROM, the data transfer between I308 and MCU is effected through the IIC bus
SCL (pin14) and SDA (pin13) of MCU. The OSD related setting data, I305 control data and other service
data, to be stored in I308.
3.5.6 P308 connector
The P308 has support keypad function. Control is give effect to for the push switch to be used when
the user changes the parameters, in order to modify the respective setting values. Whether the switch
has been pressed is identified with the switch input level that is turned "L".
Each switch input port is pulled up at outside of MCU. Related ports of I307 based on Table 1.
Each parameter is stored in the I308 EEPROM, the contents of which are updated as required.
The P308 have LED Green and Amber light, the LED Green signal pin 36 from I307 MCU, and the LED
Amber signal pin 37 from I307 MCU.
Table 1 Related ports of I307
Pin No. I/O Signal name Function Remarks
Pin 3 I KEY_POWER Soft power switch input Power key
Pin 2 I KEY_MENU Exit/Enter switch input Enter / withdraw from
OSD
Pin 41 I KEY_DOWN switch input Down key
Pin 42 I KEY_MINUS switch input - / Mute key
Pin 1 I KEY_PLUS switch input + / Auto key
3.5.7 Audio control function
The I307 MCU output signal control audio mute and power, the pin33 is mute signal, the pin32 is
controlled audio power signal.
3.5.8 Scaler programmed function
The I307 MCU is used DDR direct bus, between I305 MST8111B and MCU I307.
3.5.9 ISP and DDC2Bi function
The DDC2Bi is VESA standard for the host PC system, it can through DDC2Bi bus control LCD monitor.
The I309 will off DDC_CLK and DDC_DAT signal, when LCD monitor is no power.
Can use ISP function for firmware modification.
The pin29 is bus clock (DDC_CLK), the pin28 is bus data (DDC_DAT). It is same of the IIC data bus.
3.5.10 The power save sequence function
First disable I307 pin31 (BKLT_EN) from H to L of LCD module back light power, delay some time, then
disable I307 pin9 (PANELVCC_EN) from H to L of LCD module power, and disable I307 pin32
(AUDIO_EN) from H to L of audio power, and through 3-wire bus programmed I305 MST8111B to
power down mode.
Page 6
AL1702
3.6 Audio (Circuit diagrams MAIN PWB 8 of 8) [OPTION]
3.6.1 P309 connector
The audio signal input received from the audio input terminal P309 from the jack input of the jack
board, P309 is applied to amplifier I311 of pin4 (L-CH) and pin9 (R-CH) through the low-pass filter
consisting of R417, R418, C419 and C420.
3.6.2 P310 connector
The audio signal is output to the audio output terminal P310, and to the internal speaker system.
3.6.3 I310 MOSFET
I310 MOSFET (CEM9435A) is cut audio power (12V) for the power save sequence. The signal
(AUDIO_EN) is ON/OFF I310 MOSFET through the Q311 control.
3.6.4 I311 amplifier
The I311 TDA7496L is audio amplifier, I311 operated power voltage is 12V.
I311 pin4 and pin9 is audio input port.
I311 pin14 and pin17 is audio output port.
I311 pin 12 is mute input from I307 MCU. The pin 6 is audio volume from the I305 MST8111B.
4 Others
4.1 Detection of POWER switch status
The MCU identifies the ON status of the two power supplies. The identification is made when the
power supply is turn off. For example, if the power supply is turn off with the POWER switch, the
POWER switch must be turn on when active the power supply again. If the power supply is turned off
by pulling out the power cord, then this power supply can be turned on by connecting the power cord,
without pressing the POWER switch.
4.2 Display mode identification
4.2.1 Display mode identification
The display mode of input signal is identified based on Table 2.
When the mode has been identified through the measurement of horizontal and vertical frequencies,
the total number of lines is determined with a formula of "Horizontal frequency / Vertical frequency =
Total number of number of lines". Final identification can be made by examining the coincidence of the
obtained figure with the number of lines for the mode identified from the frequency. The Distinction
Hsync and Vsync of each mode is shown in Table 3.
When the detected frequency if the sync signal has changed, the total number of lines should be
counted even through it is range identified frequency in the same mode.
4.2.2 Out of range
This out of range mode is assumed when the frequency out of the horizontal / vertical signal is as
specified below.
Vertical frequency : 56 ~ 76 Hz.
Horizontal frequency : 30 ~ 81.1KHz.
4.2.3 Power save mode
The power save mode is assumed when the horizontal / vertical signals are as specified below.
If there is no horizontal sync signal input.
If there is no vertical sync signal input.
If the horizontal sync signal is outside the measuring range of MST8111B.
If the vertical sync signal is outside the measuring range of MST8111B.
Page 7
AL1702
Table 2 video mode
Mode Resolution H-Freq Band Width Polarity
(KHz) (MHz) H V
1 720x400 (70Hz) 31.469 28.322 - +
2 640x480 (59.94Hz) 31.469 25.175 - -
3 640x480 (66.67Hz) 35 30.24 - -
4 640x480 (72Hz) 37.861 31.5 - -
5 640x480 (75Hz) 37.5 31.5 - -
6 800x600 (56.25Hz) 35.156 36 + +
7 800x600 (60Hz) 37.879 40 + +
8 800x600 (72Hz) 48.077 50 + +
9 800x600 (75Hz) 46.875 49.5 + +
10 832x624 (74.55Hz) 49.722 57.28 - -
11 1024x768 (60Hz) 48.363 65 - -
12 1024x768 (70Hz) 56.476 75 - -
13 1024x768 (75Hz) 60.023 78.75 + +
14 1152x864 (75Hz) 67.5 108 + +
15 1280x960 (60Hz) 60 108 + +
16 1280x1024 (60Hz) 63.981 108 + +
17 1280x1024 (75Hz) 79.976 135 + +
Table 3 the Hsync, Vsync distinction
Indication Distinction Hsync Distinction Vsync The fixed
resolution mode
720 x 400 30.5KHzfH32.5KHz 69HzfV71Hz 1
640 x 480 30.5KHzfH32.5KHz 59HzfV61Hz 2
34KHzfH36KHz 65.7HzfV67.7Hz 3
36.9KHzfH38.9KHz 71.8HzfV73.8Hz 4
36.5KHzfH38.5KHz 74HzfV76Hz 5
800 x 600 34.2KHzfH36.2KHz 55.3HzfV57.3Hz 6
36.9KHzfH38.9KHz 59.3HzfV61.3Hz 7
47.1KHzfH49.1KHz 71.2HzfV73.2Hz 8
45.9KHzfH47.9KHz 74HzfV76Hz 9
832 x 624 48.7KHzfH50.7KHz 73.5HzfV75.5Hz 10
1024 x 768 47.4KHzfH49.4KHz 59HzfV61Hz 11
55.5KHzfH57.5KHz 69HzfV71Hz 12
59KHzfH61KHz 74HzfV76Hz 13
1152 x 864 66.5KHzfH68.5KHz 74HzfV76Hz 14
1280 x 960 59KHzfH61KHz 59HzfV61Hz 15
1280 x 1024 62.9KHzfH64.9KHz 59HzfV61Hz 16
1280 x 1024 79KHzfH81KHz 74HzfV76Hz 17
Page 8
AL1702
4.3 Power ON sequence
When the POWER switch is pressed, the POWER OFF signal is turned "H". when this "H" potential is
detected, the CPU begins to establish the respective power supplies according to the sequence show below.
Power Switch
157 ms
LED_G (LED)
1.8 sec
PANELVCC_EN
(Panel VCC)
1.84 sec
PCLK/DATA
(LVDS bus)
2 sec
BKLT_EN
(Backlight Power)
2 sec
AUDIO_EN
(Audio VCC)
4.4 Power OFF sequence
When the POWER switch is pressed, while the power supply is ON, the POWER ON signal is turned "H".
when this "H" potential is detected, the CPU begins to turn off the respective power supplies according to
sequence show below.
Power Switch
LED_G
(LED) 90 ms
PANELVCC_EN
(Panel VCC) 350 ms
PCLK/DATA
(LVDS bus) 316ms
BKLT_EN
(Backlight Power) 90 ms
AUDIO_EN
(Audio VCC) 1.55 sec
Page 9
AL1702
4.5 List of I/O Pin Assignments of the I307
Pin No. Port Signal Name Initial Function
Setting
3 P5.0 KEY_POWER H ON/OFF monitor power
2 P5.1 KEY_MENU H OSD enter/exit enable
1 P5.2 KEY_PLUS H OSD right enable
42 P5.3 KEY_MINUS H OSD left enable
41 P5.4 KEY_DOWN H OSD down enable
38 P1.0 LED_G H LED green enable
37 P1.1 LED_A H LED amber enable
20 P1.2 SCL H Clock of 3-wire bus for scaler
21 P1.3 SDA H Data of 3-wire bus for scaler
22 P1.4 CSZ H Chip select of 3-wire bus for scaler
25 P1.5 HWRESET H Reset enable to scaler
29 P3.0 RXD H UART interface data IN
28 P3.1 TXD H UART interface data OUT
19 P3.2 INT H Interrupt signal from the scaler
13 P3.4 ISDA H EEPROM data bus
14 P3.5 ISCL H EEPROM clock bus
27 P6.0 DDC_WP L DDC EEPROM write protection
26 P6.1 VGA_DET H VGA cable connected
9 P6.3 PANELVCC_EN L Panel power enable
31 P6.5 BKLT_EN L Back light power enable
32 P6.6 AUDIO_EN L Audio power enable
33 P6.7 MUTE L Audio mute enable
Note : Other I/O pin assignments of the I305 MST8111B
73 PWM0 BKLT_ADJ - Backlight brightness control
74 PWM1 VOLUME - Audio volume control
Page 10
AL1702
1. No display of screen (Screen is black, color of LED is amber)
Does OSM display when you push
PROCEED buttom.
No Proceed "No OSM display" section.
When a sugnal isn't being inputed, it is
indicated with "VIDEO INPUT". it is
indicated with "OUT OIF RANGE" at the Yes
time of the frequency that it can't be
distinguished.
Check if the sync signal from computer is
output and if the video cable is connected
normally.
Input the sync signal of computer, or
NG
change the cable.
OK
Proceed "checking the resolution change
IC movement" section.
Page 11
AL1702
2. Nothing displays on screen (Screen is black, color of LED is green)
Is backlight lit?
NG Refer "Checking the backlight unit" section"
OK
Does computer output RGB video Check the video cable for failure. Check the host for output
signals? signal with all black only.
1)Change pattern of video signal output on the host.
NG 2)Rsconnect the video cable.
OK 3)Change the video cable.
Check OSM menu is display on screen
when you push the "PROCEED" key.
Check if the LCD video signal cable is connected between the
NG
MAIN PWB and LCD module.
OK
Failure Point
NG
OK The cable is disconnected.
Proceed "Abnormal sreen" dection"
Next Page
Page 12
AL1702
Continue
Check the 3.3V power are supplied on I302, pin2, 4.
Check if the voltage on I302 pin3 that is
NG
power DC at 5V.
Failure Point
1) Printed wire broke between P301 pin1,
NG
OK 2 and I302.
OK
2) Check power board.
Failure Point
I302 is failure
Check the 2.5V power are supplied on I302, pin2, 4.
Check if the voltage on I302 pin3 that is
NG
power DC at 5V.
Failure Point
1) Printed wire broke between P301 pin1,
NG
OK 2 and I302.
OK 2) Check power board.
Failure Point
I302 is failure
Next Page
Page 13
AL1702
Continue
Check the 5V power are supplied on
P305 pin 1, 2, 3 (to the LCD panel)
Check if theVoltage on I312 pin2 that is
NG
DC power at 5V.
Failure Point
NG 1) FB314 is open.
OK 2) Printed wire broke between P305 pin1, 2, 3,
FB304, and P301 pin1, 2.
Check if the TTL level on I312 pin,1
that TTL level is low.
OK
Check the PANELVCC_EN signal of the
NG rectangle input Q303 pin2 at TTL high
OK level.
Failure Point
Failure Point
NG
I312 is failure. OK 1) Prined wire broke between Q303 pin
3, R309, R308 and I312 pin1.
2) Q303 is failure.
Failure Point
Check the P305 all LVDS signals.
1) Printed wire broke between Q303 pin 2 and
I307 pin9.
2) I307 is failure.
Failure Point
NG
OK 1) Printed wire broke betweenP305 and
I305 LVDS signals.
2) I305 is failure.
Failure Point
1) The LVDS cable broke between P305
and LCD module.
2) LCD module is failure.
Page 14
AL1702
3. Checking the back light unit
Is +12V supplied to inverter PWB ? (by
the power board)
Failure Point
NG
1) Inverter cable disconnection.
OK
2) Power board failure.
Check the BKLT_EN signal of the
rectangle input P301 pin 6 at TTL high
level.
Failure Point
NG 1) printed wire broke between P301 pin6,
OK R306 and I307pin 31.
2) I307 is failure.
Check the BKLT_ADJ signal of the input
P301 pin5 from I305 pin73 is a PWM
signal.
Failure Point
NG 1) printed wire broke between P301 pin5,
OK Q301, Q302 and I305 pin73.
2) I305 is failure.
Failure Point
Back light unit of LCD module is failure.
Page 15
AL1702
4. Abnormal screen
Check the R, G, B video signal from computer
input on P302 of video connector.
NG Failure Point
OK 1) No R, G, B video signals output from host
computer, check computer.
2) Video signal cable disconnection.
Check the R, G, B input video signals on I305
pin63, 60, 58 respectively that their level is 0.5
to 0.7Vp-p.
NG Failure Point
OK In the case of the Red signal. (A Green and
Blue signal is the same path, too.)
1)Printed wire broke between P302 pin 9 and
I305 pin63.
2) Video cable is failure.
3) R322 is short or open.
4) R318 is short or open.
Check all LVDS signals being output to P305 5) C332 is short or open.
from I305?
NG Failure Point
OK
Printed wire broke between I305 and P305.
Prpcess "Checking the resolution change IC
movement" section.
Page 16
AL1702
5. Abnormal OSM display adjust problem
Check the input TTL level whether was changed when
pressed function keys on the P308 pin3, 4, 5, 6. (normal is
high level, when push buttom, generated low level plus)
NG Failure Point
OK
1) Function key wire disconnection.
2) Function key wire is failure.
3) Function key board is failure.
Check the input TTL level whether was changed when
pressed function keys on the I307 pin1, 2, 41, 42. (normal
is high level, when push buttom, generated low level plus)
NG Failure Point
1) Printed wire broke between P308 pin3 and I307 pin41.
OK 2) Printed wire broke between P308 pin4 and I307 pin2.
3) Printed wire broke between P308 pin5 and I307 pin1.
4) Printed wire broke between P308 pin6 and I307 pin42.
5) C404, C405, C406, C407 is short.
6) R367, R368, R369, R370 is short or open.
Failure Point
I307 is failure.
Page 17
AL1702
6. Abnormal plug and play operation
Confirm the host computersupplies DDC2 mode.
NG Failure Point
OK
The host machine is not communicatiog in DDC2
mode.
Check the voltage on P302 pin13 that is power DC
5 V.
NG Failure Point
OK TheVideo cable is failure.
Check the voltage on I304 pin8 that is power DC 5
V.
NG Failure Point
1) Printed wire broke between I304 pin8, D309,
OK
D310 and P302 pin13.
2) D309 or D310 is failure.
3) D315 is failure.
Check the voltage on P302 pin11, 12 that is serial
data / clock signal.
NG Failure Point
OK
TheVideo cable is failure.
Check the output signal of serial data / clock on I304
pin5, 6.
NG Failure Point
OK
I304 is failure.
Failure Point
1) Printed wire broke between I309 pin2, 3, I304
pin5, 6 and P302 pin11, 12.
2) I309 maybe failure.
3) R336, R337 is open.
4) C349, C350 is short.
Page 18
AL1702
7. Checking the interface circuit of sync signal
7.1 Checking the control circuit of horizontal sync pluse
Check the horizontal sync signal on P302 pin3 TTL
level.
Failure Point
NG
OK Video cable is failure.
Check the horizontal sync signal on I305 pin37 TTL
level.
NG Failure Point
OK
1) Printed wire broke between P302 pin3 and
I305 pin37.
2) FB313, R329 open.
3) R331, C346 short.
Failure Point
Process "Checking the resolution change IC
movement" section.
7.2 Checking the control circuit of vertical sync pluse
Check the horizontal sync signal on P302 pin2 TTL
level.
NG Failure Point
OK
Video cable is failure.
Check the horizontal sync signal on I305 pin36 TTL
level.
NG Failure Point
OK
1) Printed wire broke between P302 pin3 and
I305 pin36.
2) FB312, R328 open.
3) R330, C345 short.
Failure Point
Process "Checking the resolution change IC
movement" section.
Page 19
AL1702
8. Checking the resolution change IC movement
Check +3.3V supply on I305 pin11, 21, 84, 94, 104, 114, 126, 55,
65, 35, 45, 51, 53.
NG Proceed " Checking the DC/DC converter circuit" section.
OK
Check +2.5V supply on I305 pin18, 87, 97, 117.
NG Proceed " Checking the DC/DC converter circuit" section.
OK
Check X301 14.318MHz clock input to I305 pin33 and 34 at TTL
level.
Failure Point
NG
1) Printed wire broke between X301 and I305 pin33, 34.
OK
2) C371, C375 short or open.
3) X301 failure.
Check I305 pin32 HWRESET signal is low level at normal
operation.
Failure Point
NG
1) Printed wire broke between I305 pin32 and I307 pin23.
OK
2) R410, R380 open.
3) I307 failure.
Check I305 pin69, 70, 71 3-wire bus signal is (Same of the IIC
signal).
Failure Point
NG 1) Printed wire broke between I305 pin69, 70, 71 and I307 pin20, 21,
OK 22.
2) I307 failure.
Failure Point
I305 failure.
Page 20
AL1702
9. Checking the DC/DC converter circuit
Check the 5V is output from P301 pin1, 2
NG Failure Point
OK
1) Power wire disconnection.
2) Power board is failure.
Check the 5V is input to I302 pin3.
NG Failure Point
OK
1) Printed wire broke between P301 pin1. 2
and I302 pin3.
2) FB301, FB302 open.
Check the 3.3V is output from I302 pin2, 4.
Failure Point
NG
OK I302 is failure.
Check the 5V is input to I301 pin3.
NG Failure Point
OK
1) Printed wire broke between P301 pin1. 2
and I301 pin3.
2) FB301, FB302, FB305 open.
Check the 2.5V is output from I301 pin2, 4.
Failure Point
NG
OK I301 is failure.
Failure Point
1) Printed wire broke between I301 pin2. 4, I302
pin2, 4 and I305 MST8111A power supply pin.
2) FB314, FB315, FB316, FB317, FB318, FB319
open.
Page 21
AL1702
10. Checking the Audio circuit [OPTION]
Check the Audio signal input to P309
NG Failure Point
OK
1) Audio wire disconnection.
2) Audio Jack board failure.
Check the 12V is input to I310 pin5, 6, 7, 8.
Failure Point
NG 1) Printed wire broke between P301 pin7. 8
and I310 pin1, 2, 3.
OK
2) FB320 open.
3) Printed wire broke between I307 pin32 and
I310 pin4.
4) Q311 failure.
5) I310 failure.
Check the 12V is input to I311 pin15, 16.
Failure Point
NG
1) Printed wire broke between I310 pin5, 6, 7,
OK
8 and I311 pin15, 16.
2) L301 open.
3) C412 short.
Check the VOLUME PWM signal input to I311
pin6.
NG Failure Point
OK
1) Printed wire broke between I305 pin74 and
I311 pin6.
2) C422 short.
3) I305 failure.
Check the MUTE signal is input to I311 pin12 at
high level.
Failure Point
NG
1) Prined wire broke between I307 pin33 and
OK
I311 pin12.
2) C414 short.
3) I307 failure.
Check the Audio output signal to Speaker.
Failure Point
NG
1) Speaker failure.
OK
2) Prined wire broke between I311 pin14, 17
and P310.
3) C415, C418 open or short.
Failure Point
I311 failure.
Page 22
AL1702
11. Checking inverter board circuit
Check C101 pin is around .
On/off pin of P802 is over 2V.
Brightness pin is between 0V and 3.5V.
NG
OK It is not inverter problem.
Check pin 5 of I101 is 5V.
NG
OK Check Q106, Q102 and repair them.
Check CN102, CN103 is connected
right.
NG Check CCFL and repair them.
OK
Check pin 3 of I101 is over 2V.
NG Check R128 and repair it.
OK
Check pin 18 of I101 is triangle
pulse.
NG Check C115, R108, I101 and repair
OK them.
Check pin 4 of I101 there is soft start
edge up to 4V and pin 11, 12, 19, 20
there is some pulse output.
Repair I101.
NG
OK
Check pin 2 of I101 there is below
2V from output detection.
NG Check C128/C129/C132/D115/
OK D114/C118 and repair them.
Check full-bridge (I102, I103, D102,
D103, C123) work right.
Repair them.
NG
OK
Check transformer (T101) work right.
and repair it.
Page 23
AL1702
12. Power Board
Check output voltage +5V, +12V and 22V
is right or not.
Yes
No It is not power board problem.
Check power switch is turn on or not.
No
Yes Turn switch on.
Check power cord (P801), signal
cable (P302), P802, P803, CN102,
CN103 is connected right or not.
No Connect it right
Yes
Check C805 is about DC140V-330V
or not.
Check F801, D801, P801 and repair
No
Yes them.
Check C807 is over 10V or not.
No Check R805, R803, I801 and repair
Yes them.
Check pin 6 of I801 have same
pulse or not.
Check peripheral co,of I801 and
No repair them.
Yes
Check pin 1 of T802 have same
pulse or not.
No Check Q803, R813, R814, D806,
Yes R812 and repair them.
Check peak voltage of R811 triangle
pulse is up to 1 volt or not.
Check D804, R807 and repair them.
No
Yes
Check D809, D810, D811, C818,
C817, C822, T802 have same short
circuit, or the output +5V/+12V/+22V
is over load.
No Repair them.
Yes
Check feedback circuit around I802,
I803 and the other components and
repair them.
Page 24
AL1702
3. Recommended Parts List
Note: 1. If you have spare parts need, please check BOM to get the last release part number and
related information.
No. Location Part Number Description
1 I301 6442036518 IC Linear AIC 1117-25CETR TO-252
2 I302 6442023326 IC Linear AIC 1084-33CM TO-263
3 I304 6448018208 IC 24LC02B SOP-8 MICROCHIP
4 I304 6448018218 IC M24C02 SOP-8 ST
5 I305 6444015206 IC MST8111B QFPQ-128 Mstar
6 I308 6448016508 IC 24LC16B SOP-8 MICROCHIP
7 I308 6448016518 IC M24C26 SOP-8 ST
8 I312 6444014708 FET P-Channel AO3401 SOT-23 AOS
9 I307 6448015578 IC MTV312MV64-AJ PLCC44 Myson
10 X301 6449006400 Crystal 14.318MHz AT-49 TOPICS
11 X302 6449004820 Crystal 11.0592MHz AT-49 TOPICS
12 I311 6442023100 IC Amplifier TDA7496L PDIP20 ST
13 L301 6111456131 Coil Choke 45uH DRWW 10x10
Page 25
2 3 4 5 6 7 8 9 10 11 12 13 14 15
REVISIONS
1
AUTH ZONE LTR ECN DESCRIPTION DATE APPROVED
1-1 Carol
A
A RELEASE FOR PRELIMINARY
4